The exemplary embodiments described herein relate to casing removal operations.
The plug and abandonment (PA) of wells in offshore operations have two very important aspects addressed in the present disclosure. The critical issues associated with PA activities in offshore areas, especially in deep water, are safety and ecological environment protection. PA operations require cost and technologically effective methods. Determination of cutting depths and prediction or estimation of the forces required to pull and remove a portion of the casing lining a wellbore after cutting is becoming a very important set of information. The existing standard method to define free casing (also referred to herein as “pipe”), or pipe that is not bonded, is typically performed using a cement bond log (CBL) and often in conjunction with an ultrasonic device.
The evaluation of casing bond integrity is typically looked at for distinction between free pipe versus the extent of bonding of the pipe to determine a target cutting depth. The previous methods qualitatively define the least amount of force to pull the portion of the casing with minimized risk of having some stuck point above cutting depth. The determination of the depth to cut and pull a casing sometimes involves a trial and error process, which often leads to increased costs and time required to complete the project. The industry needs more accurate and predictable methods to determine optimal cutting depths.